FAQ
TL;DR: For 2003 Fiat Stilo key work, ELM327 + MultiECUScan works; some clones need removing 1 resistor. "Yes. It will work." [Elektroda, mattm, post #17032406]
Why it matters: This helps DIY Stilo owners pick the right interface, avoid BCM comm issues, and know immobilizer limits.
Quick Facts
- ELM327 USB and Bluetooth variants are confirmed working on Stilo; Wi‑Fi was not tested by that user. [Elektroda, mattm, post #17032445]
- Some ELM327 clones bridge CAN with 120 Ω between pins 6 and 14; removing it restores BCM access. [Elektroda, mattm, post #17034767]
- Use MultiECUScan (or FiatECUScan) with an ELM327 for Stilo key programming and diagnostics. [Elektroda, mattm, post #17032371]
- MES shows a Key Programming function, but blank chips often fail; use a Megamos Crypto 48 pre‑coded for your car. [Elektroda, ste, post #17032595]
- Before any mod, run MES DTC Scan/Scan to see which modules are detected. [Elektroda, mattm, post #17034767]
Which cable and software do I need to program a 2003 Fiat Stilo key?
Use an ELM327 OBD‑II interface with MultiECUScan (MES) or FiatECUScan. Users report programming Stilo keys with this combo. Start with a decent ELM327, then pair it to MES on a laptop for access to key routines. [Elektroda, mattm, post #17032371]
Does an ELM327 OBD2 cable actually work for Stilo key programming?
Yes. “It will work.” Some Stilo modules can need a minor interface mod, but ELM327 with MES handles key programming. If BCM access fails, check the resistor guidance below before retrying the procedure. [Elektroda, mattm, post #17032406]
Do I need to modify my ELM327 to access the Body Computer (BCM)?
Check your unit. Some clones have a 120 Ω link between pins 6 and 14. If you measure 120 Ω across those pins, remove that resistor to restore CAN communication with the BCM. Confirm with scans before any hardware change. [Elektroda, mattm, post #17034767]
How can I test if my interface sees the BCM before modifying it?
Open MultiECUScan. Use DTC Scan and Scan to list detected systems. If the BCM appears, you can proceed without hardware changes. If not, measure between pins 6 and 14; a 120 Ω reading points to the removable link. [Elektroda, mattm, post #17034767]
Which ELM327 version should I buy: USB, Bluetooth, or Wi‑Fi?
USB and Bluetooth versions were confirmed working by a user who tried both. The same user did not test Wi‑Fi. For a proven path, choose USB or Bluetooth for your Stilo key work. [Elektroda, mattm, post #17032445]
Can MultiECUScan program the remote locking on a Stilo?
Yes. A user restored a non‑working remote using an ELM327 and the mentioned software. Connect to the BCM in MES and run the key programming routine to pair the remote. [Elektroda, mattm, post #17032623]
Can MultiECUScan code a brand‑new immobilizer transponder?
Not with a clean chip. MES lists a key programming function, but the transponder must be a Megamos Crypto 48 pre‑coded for your car. Blank chips are unlikely to program successfully. [Elektroda, ste, post #17032595]
What transponder chip type does the 2003 Stilo use?
Megamos Crypto 48. Ensure the transponder is pre‑coded for your specific Stilo before attempting immobilizer programming in MES, or the process can fail. [Elektroda, ste, post #17032595]
Step‑by‑step: How do I prep my ELM327 for BCM access?
- In MES, run DTC Scan/Scan to see which systems are detected.
- If BCM is missing, measure resistance between OBD pins 6 and 14.
- If you read 120 Ω, locate and remove the internal resistor, then rescan. [Elektroda, mattm, post #17034767]
What if the remote works but immobilizer coding fails?
Treat them as separate tasks. Remote pairing is achievable with ELM327 and MES. Immobilizer coding fails without a pre‑coded Megamos 48 chip. “The remote control to open the door is like that. But an immobilizer can be a problem.” [Elektroda, mattm, post #17036845]
Does FiatECUScan work, or do I need the newer MultiECUScan?
Both names are used for Stilo key work. Pair your ELM327 with MultiECUScan (current name) or the older FiatECUScan to access key procedures. [Elektroda, mattm, post #17032371]
How do I start key programming in MES once BCM access works?
Connect to the Stilo’s BCM in MES, then open the Key Programming procedure and follow the on‑screen prompts. This function is present in the software’s adjustment routines. [Elektroda, ste, post #17032595]
Where can I read more about the ELM327 CAN modification?
See the conversion guides linked in the thread that show the 120 Ω removal and discuss BCM communication. They’re shared as references for Fiat interfaces. [Elektroda, mattm, post #17032406]
